NilPy break / continue

• Type: feature (Track N — Nil-Python frontend; pyparser.inc loop lowering).
• Status: backlog
• Found: 2026-07-17, building the NilPy Tk poll loop for the IDE demo — a natural while ...: if ...: break did not compile.
• Owner: —

Gap

break (and almost certainly continue) are not in the NilPy v1 subset:

def main() -> None:
    i = 0
    while i < 10:
        if i == 3:
            break        # pascal26: error: expected expression
        i = i + 1

break → pascal26:N: error: expected expression. Both are core Python control flow; their absence forces flag-variable workarounds (running = 1; while running == 1: ... running = 0) that are un-Pythonic and error-prone.

Scope

• Lower break / continue inside while and for to the IR's existing loop-exit / loop-continue targets (the Pascal frontend already has these — reuse the shared IR loop labels, no new IR op needed → pure Track N frontend work).
• Respect nesting: break targets the innermost loop only.
• Reject break/continue outside a loop with a clear diagnostic.

Acceptance

• The snippet above compiles and prints 0 1 2 (loop exits at 3).
• continue skips to the next iteration.
• A test/test_nilpy_break_continue.npy regression; make test-nilpy green.

Note

Found alongside a NilPy str + str concatenation gap (also rejected) — that likely belongs to [[feature-nilpy-collections-and-string-methods]]; verify and fold there rather than duplicating.